Tree shaking machines utilizing vibrating jaws for imposing a vibratory force on tree trunks have been in use for many years for harvesting fruit and nuts. Various types of tree shaking machines have been developed for this purpose, which machines are structurally different in many ways, for example, as to the manner in which the vibration force is achieved and as to the manner in which the machine engages the tree.
Trunk-type tree shakers generally involve the use of a pair of clamping jaws which are adapted to engage the trunk of the tree to cause vibration of the entire tree. Tree shakers of this latter-mentioned type have generally utilized one nonvibratable jaw and one vibratable jaw which uses a vibrator employing one or more rotating weights which are effective in developing either a rapidly reciprocating or gyratory force, which force is transmitted to the trunk of the tree for dislodging the fruit or nuts. While the known trunk-type tree shakers have been effective in harvesting the fruit, they have been less than completely satisfactory because they cause undesirable damage to the tree, particularly because they damage the tree bark.
This disadvantage experienced with known trunk-type tree shakers appears to result from the way in which the jaws engage the tree trunk. The repetitive vibratory force patterns, which repetitive patterns may involve either the generation of a rapidly reciprocating vibratory force or the generation of a rapidly rotating gyratory force, cause the jaws to rub on the bark of the tree. Further, the mass and size of the trunk necessarily requires that the vibration force be of substantial magnitude in order to result in sufficient vibration of the tree limbs to remove the fruit or nuts. In many situations, the magnitude of the vibration force necessary to cause removal of the fruit is also sufficient to cause damage to the tree, particularly to the bark thereof.
U.S. Pat. No. 3 460 329 discloses a tree trunk shaker having three pivotally mounted pads for engaging the tree trunk at three circumferentially spaced locations. Two of the pads are mounted on pivoted arms each containing a vibration mechanism so that the tree trunk can be shaken. The pivotal mounting of the pads is undesirable because of the possibility of breakage. Also, the possibility of bark damage exists because the jaws contact circumferentially widely spaced-apart zones of the tree trunk so that relative circumferential movement between the pads and the trunk can readily occur.
Accordingly, it is an object of the present invention to provide a trunk-type tree shaker for harvesting fruits and nuts and which overcomes the above-mentioned disadvantage.
It is a further object of the present invention to provide a tree trunk shaker, as aforesaid, which utilizes a fixed jaw and two relatively movable, vibratable jaws which are arranged to encircle the tree trunk and to contact same over almost the entire circumference thereof.
A further object of the present invention is to provide a tree trunk shaker, as aforesaid, in which the jaws comprise resiliently compressible and deformable, hollow, tree trunk-engaging pads so that when the jaws are clamped on the tree trunk, the pads are deformed into snug contact with the tree trunk substantially completely encircling same and contacting same over a major portion of the circumference thereof.
It is also an object of the present invention to provide a tree trunk shaker, as aforesaid, which can be easily attached to or removed from the tree trunk, which can be easily moved about in an orchard, and which will operate efficiently for long periods of time while requiring a minimum of maintenance.
These and other objects of the present invention will be apparent to persons acquainted with devices of this type upon reading the following description and inspecting the accompanying drawings.